ROLE OF MICRONUTRIENTS an‎d ANTIOXIDANTS APPLICATION IN STIMULATING GROWTH an‎d YIELD OF FRESH EDIBLE VEGETABLES

A pot experiment was conducted at the greenhouse of Fac. of Agric., MansouraUniversity during the successive winter seasons of 2009/ 2010. This work aimed to evaluate the effect of different nitrogen levels in the presence of (Na -Molybdate (10ppm), boron (50ppm) , Na -salsalate (10ppm) and Ascorbic acid (250ppm)) asfoliar application on yield and chemical composition of lettuce (lactuca sativa, L., CV, balady) vegetables. As fore soil used in this investigation ; 24 treatments were arranged in a split- split block design with three replicates, which were the simple possible combination among two sources of N fertilizers (ammonium nitrate 33.5%N and ammonium sulfate 20.5%N ) three levels of N application (100, 125 % and 150%) of recommended doses(RD) and four treatments of foliar spraying (Na -Molybdate (10ppm), boron (50ppm) , Na -salsalate (10ppm) and Ascorbic acid (250ppm))) The obtained results can be summarized as follow: Spraying of micronutrients and antioxidants either in a single form or in combination with mineral fertilization led to a positive effect on the growth and yield of lettuce plants. The accumulation of nitrate and nitrite in lettuce fresh leaves increased as the level of mineral fertilizers increased. Foliar (Na -Molybdate (10ppm), boron (50ppm) , Na -salsalate (10ppm) and Ascorbic acid (250ppm)) resulted in pronounces decrease in the values of NO3-N and NO2-N in lettuce plant. Under the same condition of this investigation, it could be recommended that; soil addition of N fertilizers at the rate of 100% from the recommended doses for lettuce plant coupled with foliar application of Molybdate-Na is considered as the optimum treatment for producing a safe yield of lettuce plant.